Dialuric acid autoxidation. Effects of transition metals on the reaction rate and on the generation of "active oxygen" species.

The autoxidation of dialuric acid, a process which is believed to be of crucial importance in the diabetogenic action of alloxan, was found to be strongly catalysed by copper, iron and manganese. Superoxide radical and hydrogen peroxide were generated in both the uncatalysed and the metal-catalysed reactions. In contrast, hydroxyl radical was formed during dialuric acid autoxidation only in the presence of added iron salts. Production of the latter radical was strongly inhibited by catalase but only weakly by superoxide dismutase, implying that the metal-catalysed Haber-Weiss reaction is of comparatively little importance in hydroxyl radical generation from dialuric acid.